Umakant Kondapure, Collin Fernandes, Nipun Bhatia, Vikram Bathula and, Ketki Deshpande Solutions for Chapter: Interference and Diffraction, Exercise 2: Critical Thinking

Assertion: An excessively thin film appear black in reflected light.

Reason: The film absorbs all the radiations falling on it.

Assertion: The fringe visibility will be maximum when amplitude of light waves from two coherent sources is exactly equal.

Reason: Fringe visibility, $V=\frac{{\mathrm{I}}_{\max }}{{\mathrm{I}}_{\min }}$

In Young's experiment, the fringe width is$3 \mathrm{mm}$ for a light of wavelength $6000 \mathrm{\AA }$. If the entire apparatus is dipped in the water of refractive index $\frac{3}{2}$ then what is the change in fringe width?

In double slit experiment, fringes are obtained using light of wavelength $4800 Å$. One slit is covered with a thin glass film of refractive index $1.4$ and another slit is covered by a film of same thickness but refractive index$1.7$. By doing so, the central fringe is shifted to fifth bright fringe in the original pattern. The thickness of glass film is

Monochromatic light of wavelength $600 \mathrm{nm}$ is used in a Young's double slit experiment. One of the slits is covered by a transparent sheet of thickness $18 \mathrm{\mu m}$ made of a material of refractive index $1.6 .$ The number of fringes that shift due to the introduction of the sheet is

The distance between the first and the sixth minima in the diffraction pattern of a single slit is $0.5 \mathrm{mm}$. The screen is $0.5 \mathrm{m}$ away from the slit. If the wavelength of light used is $5000Å$, then the slit width will be

In a biprism experiment, $5^{\text {th }}$ dark fringe is obtained at a point. If a thin transparent film is placed in the path of one of waves, then $7^{\text {th }}$ bright fringe is obtained at the same point. The thickness of the film in terms of wavelength $\lambda$ and refractive index $\mu$ will be

In a biprism experiment, the micrometer readings for zero order and tenth order fringes are $1.25 \mathrm{mm}$ and $2.37 \mathrm{mm}$ respectively, when the light of wavelength $6000 \mathrm{\AA }$ is used. If the light of wavelength $7000 \mathrm{\AA }$ is used, then micrometer readings for zero order and tenth order fringes will be